When Cave Oasis enters the battlefield, sacrifice it unless you pay 2 life.
: Add or to your mana pool.
Put Cave Oasis on top of your library: Add to your mana pool.
: Cave Oasis becomes a 2/2 red Ape creature until end of turn. It's still a land.
: Add 
or 
to your mana pool.
to your mana pool. 
: Cave Oasis becomes a 2/2 red Ape creature until end of turn. It's still a land.
